The present invention relates to a system for detecting lens dirtiness of a vehicle-mounted camera or the like.
In order to prevent accidents such as collision between vehicles or collision between a vehicle and a pedestrian, a technology has been developed in which a camera monitors the status of the surrounding areas of the vehicle, and if a potential hazard is detected, the driver is given a warning, and the operation of the vehicle is automatically controlled. In a system in which the camera is mounted outside of a vehicle, a lens of the camera is likely to get dirty due to bad weather, dirt, dust and the like, and in some cases, such a lens dirtiness possibly causes a false warning, which may adversely affect safety. As a solution to this problem, a system to automatically detect lens dirtiness and remove the dirtiness by air or water is commercially available, but such a system is generally expensive. Thus, it is preferable to temporarily stop the recognition operation for the surrounding areas when the lens gets dirty heavily, so that a false warning is prevented and the safety level does not lower unnecessarily.
Patent Document 1, for example, discloses a method to detect a water droplet on the lens surface based on a differential image between a background image and an input image.
[Patent Document 1] Japanese Patent Application Laid-open Publication No. 2006-254206